The Science Thread

Yes, but they are coming only now, after decades of emitting -> wasting so much light energy …

I suspect that the amount of energy that could be recovered from a streetlamp would be miniscule, and massively outweighed by the cost of trying to capture it.

Well, it would depend on how efficient our photovoltaic cells were - but right now I think you've won.

Not really - even if photovoltaic cells were perfectly effecient, there's only so much energy emitted from a lamp bulb. And the more of that light you capture to convert back to electricity, the less light you are shining around to light the street.

Yeah, because of the "no free food" theorem (also sometimes inacurately called "Thermodynamics"), you cannot expect to extract from something that you are powering more energy that what you provide to it. So in the best case (which means neglecting all the loss sources), you would extract only the same exact amount of energy that it costed you to power the lamps (and of course, you would light nothing because you've taken back all the energy from the lamp).

The solar panels are still not very efficient, but they are sustainable because the solar energy is "free". Moreover, the light from the sun contains not only the visible light, but a lot of powerful UV and IR light, which are absent from public lighting because we don't want to produce them because we don't see them anyway.

I think that simple changes to reduce energy consumption (as "using directive light toward the ground, rather than light going in all directions", or "using low energy lamps") would be way more efficient than trying to retrieve the energy injected into street lighting.

There was a young lady named Bright.
She traveled far faster than light.
She left one day,
In a relative way
And returned home the previous night.

Pibbur who heard it on Discovery

Placebo Riddle - "A comprehensive review of clinical trials for pain medications conducted in the U.S. and other countries shows that the placebo effect has gotten considerably stronger in the past 25 years -- but only in America."
http://www.huffingtonpost.com/entry/…ection=science

Originally Posted by zahratustra
Placebo Riddle - "A comprehensive review of clinical trials for pain medications conducted in the U.S. and other countries shows that the placebo effect has gotten considerably stronger in the past 25 years -- but only in America."
http://www.huffingtonpost.com/entry/…ection=science

Pure speculation, and no offence to our American friends, but I think that contemporary America is a particularly stressed and anxious place, which can also be seen in the levels of violence. Placebos and even alternative medicines can have a very good effect on such people, because simply having a caring person in a position of authority listening to them and giving them something that offers reassurance can be very powerful.

Originally Posted by pibbur who
There was a young lady named Bright.
She traveled far faster than light.
She left one day,
In a relative way
And returned home the previous night.

Pibbur who heard it on Discovery

I read it ages ago … I think it was even in an school book …

I knew sunbathers were bad…

Oxybenzone, a common UV-filtering compound, poses a hazard to coral reefs:

Lathering up sunscreen may prevent sunburn and protect against cancer, but it is also killing coral reefs around the world.

That’s the conclusion of a team of international scientists, which includes University of Central Florida professor and diving enthusiast John Fauth.
[…]
The chemical not only kills the coral, it causes DNA damage in adults and deforms the DNA in coral in the larval stage, making it unlikely they can develop properly. The highest concentrations of oxybenzone were found in reefs most popular with tourists.

“Coral reefs are the world’s most productive marine ecosystems and support commercial and recreational fisheries and tourism,” Fauth said. “In addition, reefs protect coastlines from storm surge. Worldwide, the total value of coral reefs is tremendous. And they are in danger.”
[…]
In laboratory experiments, the team exposed coral larvae and cells of adult corals to increasing concentrations of oxybenzone. The research team discovered that oxybenzone deforms coral larvae by trapping them in their own skeleton, making then unable to float with currents and disperse.

Oxybenzone also caused coral bleaching, which is a prime cause of coral mortality worldwide. Corals bleach when they lose or expel the algae that normally live inside them, thus losing a valuable source of nutrition. In addition, coral larvae exposed to increasing oxybenzone concentrations suffered more DNA damage.
[…]
“Wear rash guards or scuba wetsuits and skip all the hygienic products when you go diving,” Fauth said. “If we could do it for a week at a time, people can certainly forgo it for a few hours to help protect these reefs for our children and their children to see.”

"Man fails paternity test because his unborn twin is the biological father of his son"
http://www.iflscience.com/health-and…is-unborn-twin

Huh? So where did that 10% of the genome come from if not the father?

"Tetragametic chimerism is a condition that occurs when embryonic cells from dizygotic twins fuse early in development, leading to the birth of a singleton with two cell lines containing different genomes" - 10% come from the twin that never was…

But those genes don't just come from nowhere. They either come from the father or mother. Not from some mystery brother…. :/

Originally Posted by Thrasher
They either come from the father or mother. Not from some mystery brother…. :/

But that's the whole point! That's exactly where they come from!
https://s3.amazonaws.com/media.guide…b18ff74829.pdf

But they don't just get created from scratch. The genes should either match the mother or father. To say neither, and claim it's from a brother is inconsistent with how I understand fertilization to happen.

Unless the fusing process in Tetragametic Chimerism scrambles the genes somehow…

Father had 2 cell lines with different chromosomes. For standard DNA test samples where taken from man's cheek. Those cells contained only that man's DNA which didn't match the DNA of the child. Then man's sperm was tested and "supporting the human chimera idea, what they found was a “major” genome, accounting for roughly 90% of the sperm cells, and a “minor” genome that only represented about 10%, Starr explained. The major genome matched up with the cheek cells, but the minor genome was consistent with the child’s DNA."

It's not possible for the cells from the same person to have different chromosomes, unless there is mutation. That's the basic fallacy of this article.

Argue with Michael L. Baird, PhD; Julie A. Heinig, PhD; Debra Davis, PhD; Kayla Sheets, MS;
Brianne Kirkpatrick, MS and D. Barry Starr, PhD Thrasher. They are convinced that it's possible.

Originally Posted by zahratustra
Argue with Michael L. Baird, PhD; Julie A. Heinig, PhD; Debra Davis, PhD; Kayla Sheets, MS;
Brianne Kirkpatrick, MS and D. Barry Starr, PhD Thrasher. They are convinced that it's possible.

Who are they and do you have any references?

My point is that the article is sensational, acting as if the genome is random. The fact is that the genome had to come from alleles in the chromosomes of the father or mother. It isn't just random genetic material coming from a mysterious source.

What's interesting is the the concept of

"Tetragametic chimerism is a condition that occurs when embryonic cells from dizygotic twins fuse early in development, leading to the birth of a singleton with two cell lines containing different genomes"